1. Field of the Invention
This invention relates to a process for producing iron such as steel and cast iron and a refractory material which process makes effective use of aluminum smelting residue produced as a by-product in the manufacture of aluminum and a scale produced as a by-product in the processing of iron products.
2. Prior Art
Aluminum smelting residue is formed on molten aluminum in the refining of metallic aluminum, in a melting treatment of scrap aluminum and in the manufacture of an aluminum alloy. The aluminum smelting residue is composed mainly of alumina and metallic aluminum. The aluminum smelting residue is pulverized or crushed and then screened so that part of the pulverized metallic aluminum is recovered. Part of the aluminum smelting residue from which part of the metallic aluminum has been removed is used for the purpose of heat insulation and slag formation, and the remainder is discarded. When the discarded aluminum smelting residue is exposed to rain water, aluminum nitride and aluminum carbide contained in the aluminum smelting reside react with water to produce ammonia gas and hydrocarbon gas which give rise to an environmental pollution.
Scale is formed during the drawing of a steel billet in a continuous casting of molten steel, during the rolling or the forging of a steel billet or ingot, and during the heat treatment of a steel billet or ingot in a furnace for a subsequence rolling or forging operation. The scale is in the form of a film or sheet and contains iron oxide as a main component. The scale is reduced and reused as iron source. It is not thought, however, that this scale is used effectively.